I use Ubuntu 16.10 with sane-backends Version: 1.0.25+git20150528-1ubuntu2

sane-genesys man page say that GL843 is supported (http://manpages.ubuntu.com/manpages/yakkety/man5/sane-genesys.5.html )So I tried to add support for it by following those basics steps :https://help.ubuntu.com/community/SANE%20-%20Installing%20a%20scanner%20that%20isn%27t%20auto-detected

That doesn't helped.

This command may give interesting infos :

$ SANE_DEBUG_GENESYS=255 scanimage -L[genesys] attach: vendor 1971 product 3103 is not supported by this backend1971 and 3103 are decimal values of vendor and product ids .

No scanners were identified. If you were expecting something different,check that the scanner is plugged in, turned on and detected by thesane-find-scanner tool (if appropriate). Please read the documentationwhich came with this software (README, FAQ, manpages).[genesys] sane_genesys_exit start[genesys] sane_genesys_exit completed

<trying to find out which USB chip is used>checking for LM983[1,2,3] ...this is not a LM983x (bcdUSB = 0x200)checking for GT-6801 ...this is not a GT-6801 (bcdUSB = 0x200)checking for GT-6816 ...this is not a GT-6816 (bDeviceClass = 255, bInterfaceClass = 255)checking for GLxxx ...this is not a GL646 (bDeviceClass = 255, bInterfaceClass = 255)<This USB chip looks like a GL843 (result from sane-backends 1.0.25git)>